ellipse interpolation

ellipse-interpolation.js

export function ellipseInterpolation(x, y, radiusX, radiusY, startProgress = 0, clockwise = true) {
  const dir = ( clockwise ? 1 : -1);
  return function (t) {
    t = (t + startProgress);
    const radian = t * Math.PI * dir * 2;
    return {
      x: radiusX * Math.cos(radian) + x,
      y: radiusY * Math.sin(radian) + y
    };
  }
}